Torque controller for permanent magnet synchronous motor

Abstract

When output voltage V 1 of an electric power converter reaches a prescribed voltage V 1 * ref , a difference between V 1 and V 1 * ref is integrated to correct a commanded torque to τo* (τ*=τo*+Δτ).

1. A torque controller for a permanent magnet synchronous motor comprising:
 an electric power converter for driving the permanent magnet synchronous motor; 
 a current command calculator for calculating two current command values for a q-axis (torque axis) and a d-axis (magnetic flux axis) based on a torque command value; and 
 a vector controller for creating two output voltage command values of the electric power converter for the q-axis and the d-axis based on two differences between the current command value and a detected current value for the q-axis and the d-axis, respectively, to control an output voltage value of the electric power converter; 
 wherein when the output voltage value of the electric power converter reaches a prescribed voltage value, an integration is performed on a difference between the prescribed voltage value and the output voltage value of the electric power converter to obtain an integrated value and the integrated value is used to correct a commanded torque value. 
 
     
     
       2. The torque controller according to  claim 1 , wherein a gain in the integration is a control response angular frequency to be set in a commanded torque correcting part, the control response angular frequency being about half to one-tenth the control response angular frequency to be set in current control by a vector control calculating part. 
     
     
       3. The torque controller according to  claim 1 , wherein an upper limit of the integrated value calculated from the difference between the prescribed voltage value and the output voltage value of the electric power converter is restricted to 0, and a lower limit of the integrated value is restricted to a value obtained by multiplying the absolute value of the commanded torque value before the correction by −1. 
     
     
       4. The torque controller according to  claim 1 , wherein the calculated frequency value is obtained from commanded voltage values for the d-axis and q-axis, and a detected motor current or a reproduced motor current so that a difference calculated from an inferred phase value and a motor phase value becomes 0. 
     
     
       5. A torque controller for a permanent magnet synchronous motor comprising:
 an electric power converter for driving the permanent magnet synchronous motor; 
 a current command calculator for calculating two current command values for a q-axis (torque axis) and a d-axis (magnetic flux axis) based on a torque command value; and 
 a vector controller for creating two output voltage command values of the electric power converter for the q-axis and the d-axis based on two differences between the current command value and a detected current value for the q-axis and the d-axis, respectively, to control an output voltage value of the electric power converter; 
 wherein the torque command value is corrected so that the output voltage of the electric power converter does not exceed a prescribed voltage value; and 
 wherein, in correction of the commanded torque value, an integration is performed on a difference between the prescribed voltage value and the output voltage value of the electric power converter to obtain an integrated value, the integrated value is multiplied by a sign of a polarity of the commanded torque value before the correction to obtain a multiplied value, and the multiplied value is added to the commanded torque value before the correction. 
 
     
     
       6. A torque controller for a permanent magnet synchronous motor comprising:
 an electric power converter for driving the permanent magnet synchronous motor; 
 a current command calculator for calculating two current command values for a q-axis (torque axis) and a d-axis (magnetic flux axis) based on a torque command value; and 
 a vector controller for creating two output voltage command values of the electric power converter for the q-axis and the d-axis based on two differences between the current command value and a detected current value for the q-axis and the d-axis, respectively, to control an output voltage value of the electric power converter; 
 wherein the torque command value is corrected so that the output voltage of the electric power converter does not exceed a prescribed voltage value; and 
 wherein, in correction of the commanded torque value, which is denoted τ*, calculations as in the equations shown below are performed by using the prescribed voltage value, which is denoted V ref *, and the output voltage value of the electric power converter, which is denoted V: 
 
       
         
           
             
               
                 
                   
                     [ 
                     
                       Equation 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       1 
                     
                     ] 
                   
                 
                 
                   
                       
                   
                 
               
               
                 
                   
                     Ka 
                     = 
                     
                       
                         ω 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         c 
                       
                       
                         
                           
                             R 
                             
                               * 
                               2 
                             
                           
                           + 
                           
                             
                               ( 
                               
                                 
                                   ω 
                                   1 
                                 
                                 · 
                                 
                                   L 
                                   q 
                                   * 
                                 
                               
                               ) 
                             
                             2 
                           
                         
                       
                     
                   
                 
                 
                   
                     ( 
                     3 
                     ) 
                   
                 
               
               
                 
                   
                     [ 
                     
                       Equation 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       2 
                     
                     ] 
                   
                 
                 
                   
                       
                   
                 
               
               
                 
                   
                     
                       Δτ 
                       * 
                     
                     = 
                     
                       
                         K 
                         s 
                       
                       · 
                       
                         ( 
                         
                           
                             V 
                             ref 
                             * 
                           
                           - 
                           
                             V 
                             1 
                           
                         
                         ) 
                       
                       · 
                       
                         
                           S 
                           ign 
                         
                         ⁡ 
                         
                           [ 
                           
                             τ 
                             0 
                             * 
                           
                           ] 
                         
                       
                     
                   
                 
                 
                   
                     ( 
                     6 
                     ) 
                   
                 
               
               
                 
                   
                     [ 
                     
                       Equation 
                       ⁢ 
                       
                           
                       
                       ⁢ 
                       3 
                     
                     ] 
                   
                 
                 
                   
                       
                   
                 
               
               
                 
                   
                     
                       τ 
                       * 
                     
                     = 
                     
                       
                         τ 
                         0 
                         * 
                       
                       + 
                       
                         Δ 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         
                           τ 
                           * 
                         
                       
                     
                   
                 
                 
                   
                     ( 
                     7 
                     ) 
                   
                 
               
             
           
         
         where τo* is the command torque value before the correction, Δτ is an amount of torque correction, τ* is a commanded torque value after the correction, Ka is an integrated gain, ω 1  is a calculated frequency value, ωc is a control response angular frequency, R is the resistance of a motor and a harness, Lq is an inductance value, and Sign[τo] is ±1. 
       
     
     
       7. A torque controller for a permanent magnet synchronous motor comprising:
 an electric power converter for driving the permanent magnet synchronous motor; 
 a current command calculator for calculating two current command values for a q-axis (torque axis) and a d-axis (magnetic flux axis) based on a torque command value; 
 and a vector controller for creating two output voltage command values of the electric power converter for the q-axis and the d-axis based on two differences between the current command value and a detected current value for the q-axis and the d-axis, respectively, to control an output voltage value of the electric power converter; 
 wherein the torque command value is corrected so that the output voltage of the electric power converter does not exceed a prescribed voltage value; 
 and wherein the prescribed voltage value is three-fourths or less of a DC voltage supplied to the electric power converter when sine wave modulation is performed on commanded voltage values Vu*, Vv*, and Vw* of a three-phase AC current, which control the electric power converter, or 2/√3 or less of the DC voltage supplied to the electric power converter when an in-phase signal which is canceled at a line voltage, is superimposed on the commanded voltage values Vu*, Vv*, and Vw* of the three-phase AC current.